<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Box model 盒子模型</title>
    <style>
        * {
            margin: 0;
            padding: 0;
        }

        div.box {
            width: 500px;
            height: 250px;
            background-color:antiquewhite;
            
            /* padding-left: 10px;
            padding-top: 20px;
            padding-right: 10px;
            padding-bottom: 20px; */

            padding: 20px 10px;

            margin-top: 50px;
            margin-left: 50px;
            /*margin-bottom: 20px;
            margin-top: 20px;
            margin-left: 10px;
            margin-right: 10px;*/
            /* margin-bottom: 20px; */
            /* padding-left: 20px; */
            /* text-align: center; */
        }
    </style>
</head>
<body>
    <div class="box">div 1</div>
    <hr>
    <div class="box">div 2</div>
    <hr>
    <div class="box">div 3</div>
</body>
</html>